I went to support with my webhost about this problem and they told me to do the following:
1. Deactivate plugins
2. Change permallink settings to “Plain”
3. Save
4. Change permalinks back to “Day and name” (the current selection)
5. Save
6. Reactivate plugins
This seems to work right now. The only glitch was having to reconnect with Jetpack by logging into wordpress.com. Not sure why or what that did, but Jetpack is now working also.
Sorry for the bother.